michael8554

If you were able to focus on the Moon, then Venus should be in focus too. But did you actually see detail on the moon, or was it a featureless blob ? The scope should be able to focus an eyepiece that came with it, without needing to add any extensions. The Moon and Venus are so far away that they can both be considered to be at "infinity". Whereas a distant landmark will only get you close to "infinity" focus, but is a good starting point if correct focus is way out. Then for best night time focus, start with the Moon if available, and then a star. Michael

Depends entirely on the guidecam performance. If it displays a lot of hot pixels that PHD2 might think are stars then make a Dark Library. Michael

Hi Franklin The Accutrak is a motor that slowly drives the mount so that the telescope follows the stars etc which appear to move across the sky. It may need adjustment of the speed knob from time to time. if the stars etc start to drift out of the eyepiece view. The S-N switch has to be set to the Hemisphere you are in. The mount itself has to be roughly "Polar Aligned", which will be explained in the Instruction Manual: https://www.telescope.com/assets/product_files/instructions/29081_9-98.pdf Although you seem to have a better mount than in the instructions, the methods remain the same. Michael

"I was trying to observe Venus through my telescope" "Although, when I observe the moon it is bright and clear" That suggest to me that if you didn't alter the focus after seeing a focused image of the moon. And looking through the eyepiece you saw a focused image of Venus. Then did you alter the focus when you tried to take the image of Venus ? If not then I can only guess you didn't have the phone positioned correctly. Michael

The Tate Modern would love your shed. Next to the pile of bricks ? From the Quaint style of architecture:

Hi Richy If you've read all the forums you'll know that a Full Spectrum mod will need at least a UV/IR filter on a refractor, to prevent "star bloat". Best mod if you are always going to use narrow-band, pollution etc filters. A good Ha modder will adjust the sensor to retain Autofocus, or if you want will add a Baader filter to compensate. Michael

There appear to be at least two "accepted" pronunciations of the word "nucleus". UK English is "nyook-lee-us" I suspect the US pronunciation is based on their shortening of the word "nuclear" to "nuke", so they say something like "nuke-lee-us". Michael

Hi Graeme Ah, so you have already uploaded logs to the PHD2 Help forum. What date was that, so I can have a look ? "I did a Star Test and the image clearly shows star Ts instead of star crosses. " That means there was Dec movement in the correct direction, instead of in the RA direction like in the Cal image you posted. Just no Dec movement when it reversed, due to huge Dec Backlash ? Can you post a link to the latest GuideLog with which has a Cal ? Michael

Hi Graeme I could ask lots of questions like: How many steps did it take to Cal RA ? What did you set the guide speed to, both RA and Dec the same ? What driver? But best to upload a link to the PHD2 GuideLog, make sure the date and time in the file name are relevant. Michael

Sorry my bad, missed a digit on my search for the native res. Yes cropping will work. Michael

"I've just snapped up an EOS 6D with only 16,000 on the clock for £220 for my whitelight solar imaging on the Evostar 150 ... " Bargin ! My used low count 6D cost £350 several years ago, I Ha modded it myself. Michael

Cropping a 1920 x 1040 image to even the full disk of the the moon would be about 350 x 250 pixels - very low res. Michael

The norm is that a dome attached to a circular concrete floor requires the pier to be isolated from the concrete. Are you sure that the dome and pier attached to the same lump of rock gives the pier the necessary isolation from vibrations ? Michael

Does it have the handbox that attaches via cable to the control panel? Without that the functionality is very limited. If it does then I would use the scope and see if there are any problems, may not need any refurbishment. Run the focus knob at the back many many turns in both directions, to each end of the focus range. This redistributes the thick grease that the big heavy mirror slides on. (Count wrist-twists so that you end up roughly back where presumably it was focused 30 years ago). There is some LX3 chat on this site: https://groups.io/g/meade-lx5-lx6/topics Michael

Hi Zak I'm not clear what you want to do here. 1) Your Nikon D3400 has a detachable lens and could be connected without the lens to the scope via a T2 Adapter. Attached to a "1.25" T2 Nosepiece" that slips into the "hole" in the focuser where the eyepiece would normally go. (That might raise a separate issue of not being able to get the camera close enough to the scope to get an in-focus image. ) 2) "but would like to have a lens for the camera too?" Do you mean a lens, or do you mean an eyepiece ? Cameras and smart phones with a non-removeable lens can take images from a telescope's eyepiece. (And avoid that separate issue I mentioned) Or you can use "Eyepiece Projection", where the camera body is attached to an eyepiece to get "high magnification" for images of planets. If it works, option 1 is the most common method Michael

If both ends are RJ and the colours run in the same order you should find one easily. But be careful, the colours may run in the same order, but may be "back-to-front". Depending on whether the cable is a "Straight Through" or a "Crossover". An Electronics Repair or PC Repair shop may be able to crimp on a new RJ plug to the existing cable. Show them the old one to get the colours the right way round. Michael

Here are two sources of star trailing in an unguided mount: 1) Polar Alignment, causes drift in Dec. That would be "up and down" if your camera was oriented with the long side of the sensor parallel to RA. Unguided the PA has to be much better than when guided. Such that your 120 sec exposure shows no drift. 2) Almost all mounts have Periodic Error in RA. A repetitive wave-like drift of RA towards east and then towards west ( "left to right" ) with a period of several minutes, the duration of the "worm period " of the mount, maybe 4 minutes in your case. When unguided all you can do is find the slowest exposure that doesn't show drift. You've already found out that 6 seconds doesn't, but you should be able to expose for longer. Michael

Many of your questions suggest you haven't read the PHD2 Instructions, or haven't understood them ? 1) Dec backlash needs at least a worm adjustment, ideally alacant's stripdown and bearing replacement. 2) "I'm disappointed that there we both approximately ~8500ms. Am I correct in thinking, that value means that when PHD2 sends a guide pulse, it believes that it is taking 8.5 seconds for the mount to respond?" The Dec axis has Backlash, so it could wobble from one end to the other of the backlash range. Once it's wobbled to one end it may take 8.5secs to move back to the middle. The PHD2 Backlash Comp can add some extra big pulses to help that along. But your Dec backlash is too large, so PHD2 won't do that, as there is then a danger of over-shooting into a repeating pattern of back and forth wobbling. 3) The first GA run reported you hadn't cleared that Dec backlash before Calibrating. PHD2 had to supply 13 pulses before Dec started moving, which marred the Cal. If you'd cleared backlash before Cal that wouldn't have happened. 4) "I note the RA PE error. Is that something that I would want to change physically (i.e. remove possible grit), or could that be trained out?" PE can be Trained if the mount has Permanent PE Correction. Strictly speaking the grit is not a PE error, it's causing a momentary spike that would be present even if the PE was perfect. 5) AFAIK the Star Tool is measuring the primary guidestar when MultiStar guiding is in action. PHD2 will select the best star(s) to guide on. Not necessarily the "very bright star", that is probably over-exposed, so has a flat top, instead of a sharp peak. That's why PHD2 is asking you to improve focus, so that star shape is as "pointy" as possible. 6) in the graphs you inserted, RA error is about twice that of Dec eg RA = 0.61arcsec, Dec = 0.38arcsecs. So stars may be elongated in the RA direction. But to an extent will depend on your imaging pixel scale. If your imaging pixel scale is much bigger than the guide errors, then the guide error is smaller than one pixel, so may not show. 6) You don't need to run the Guide Assistant for 30 mins, most of the time the suggested 2 minutes will give enough info. You can PA with SharpCap, and check in the GA run that's it good enough. Bottom line is that despite the large backlash, lucky for you your setup is guiding Dec well. It's RA that needs looking at, the grit and the PE. Michael

Hi Rich I couldn't see what you described so I stretched your image: I can see vignetting, which as an experienced imager I'm sure you're aware of. More concerning are the vertical lines all over the image. Michael

Hi Chubster I haven't got the latest PHD2 dev yet, so I can only guess that you click on each explanation to expand it. The Cal was accepted, but Advised that there was an Orthog error that might be worth improving. That might be due to a large Polar Alignment error ? Or failure to clear Dec Backlash before Cal ? The RA and Dec Guide Rates that PHD2 measured might have been noticeably different from each other. Hard to tell what's going on without a GuideLog to evaluate. Michael

For years the PHD2 guys said Polar Alignment can be no worse than 5arcmins to get good guiding. Recently after years of improving PHD2 they are quoting no worse than 10arcmins. So you didn't need to worry about a 4 arcmin error. Did PHD2 flag it up as a problem in the GA run ? No. It would have if it was too much. It did flag up exposure, focus, and Dec Backlash. From the GuideLog. There was about 25arcsecs of Periodic Error in RA. There are regular spikes in RA, may be dirt or grit at one point on the worm. Apart from those spikes, RA and Dec guiding looked to be under 1 arcsec. Focus actually got worse as the night went on HFD = 6.72pixels ! Use the PHD2 Star Profile window to reduce that to a minimum. Michael

Oops, you mentioned it worked with Artemis in your first post 😆 If there's a APT forum, contacting that would be the next step. Michael

Reduced to 357mm FL, the pixel scale would be 2.17arcsec/pixel. Unreduced it's 1.85arcsec/pixel. Michael

Doesn't appear to be between rotating parts, so perhaps It's some sort of dust gasket ? Probably fine without it. Make sure the bolts don't "bottom out" when tightening. Michael

Does it work with Artemis Capture, Atik's capture software for that camera ? Michael